Display device

ABSTRACT

A display device includes a flexible substrate including a first region including a display region, a second region including a curved region, and a third region including a terminal region; an electro-optical element located in the display region; and a resin layer continuously extending from the first region to the third region.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priority from theprior Japanese Patent Application No. 2017-127062, filed on Jun. 29,2017, the entire contents of which are incorporated herein by reference.

FIELD

The present invention relates to a display device, and specifically, adisplay device including a flexible substrate as a support substrate.

BACKGROUND

Recently, a sheet-like display device including a substrate that isflexible (hereinafter, referred to as a “flexible substrate”) as asupport substrate has been progressively developed. Such a displaydevice including a flexible substrate is foldable, and has an advantageof, when being incorporated into a housing of a mobile terminal or thelike, allowing a peripheral portion (bezel portion) of a display screento be decreased in size.

Generally, a display region of a display device has various signal linessuch as scanning signal lines, video signal lines and the like locatedtherein. These signal lines extend to a terminal region located in thevicinity of the display device, and are connected with a flexibleprinted circuit board (FPC board). Therefore, a support substrate has aplurality of lines and the terminal region provided thereon in additionto the display region. For example, United States Patent ApplicationPublication No. 2016/0172428 discloses a technology by which the displaydevice is folded along a region between the display region and theterminal region and the terminal region is folded back toward a rearsurface of the display region to decrease the size of the bezel portionof the display screen.

SUMMARY

A display device in an embodiment according to the present inventionincludes a flexible substrate including a first region including adisplay region, a second region including a curved region, and a thirdregion including a terminal region; an electro-optical element locatedin the display region; and a resin layer continuously extending from thefirst region to the third region.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view showing a structure of an organic EL displaydevice in embodiment 1;

FIG. 2 is a cross-sectional view showing a structure of the organic ELdisplay device in embodiment 1;

FIG. 3 is a cross-sectional view showing a structure of the organic ELdisplay device in embodiment 1;

FIG. 4 is a cross-sectional view showing a structure of a pixel of theorganic EL display device in embodiment 1;

FIG. 5 is a cross-sectional view showing a structure of an end portionand the vicinity thereof of a display region of the organic EL displaydevice in embodiment 1;

FIG. 6 is a cross-sectional view showing a structure of a liquid crystaldisplay device in embodiment 2; and

FIG. 7 is a cross-sectional view showing a structure of the liquidcrystal display device in embodiment 2.

DESCRIPTION OF EMBODIMENTS

According to United States Patent Application Publication No.2016/0172428, in the case where the display device is folded along theregion between the display region and the terminal region, there occursa problem that lines connecting the display region and the terminalregion to each other are damaged and easily corroded. United StatesPatent Application Publication No. 2016/0172428 describes that in orderto protect the lines, a protective film is provided on the curvedregion, along which the display device is folded. However, production ofthe structure described in United States Patent Application PublicationNo. 2016/0172428 requires an additional step of forming the protectivefilm on the curved region, which increases the number of productionsteps.

One object of the present invention is to provide a display deviceprotecting lines in such a folded portion with no additional productionstep.

EXPLANATION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the drawings and the like. The present invention may becarried out in various forms without departing from the gist thereof,and is not to be construed as being limited to any of the followingembodiments.

In the drawings, components may be shown schematically regarding thewidth, thickness, shape and the like, instead of being shown inaccordance with the actual sizes, for the sake of clearer illustration.The schematic drawings are merely examples and do not limit theinterpretations of the present invention in any way. In thespecification and the drawings, components that have substantially thesame functions as those described before with reference to a previousdrawing(s) bear the identical reference signs thereto, and detaileddescriptions thereof may be omitted.

In the specification and the claims, an expression that a firstcomponent is “on” (or “above” or “below”) a second component encompassesa case where the first component is in contact with the second componentand also a case where the first component is above or below the secondcomponent, namely, a case where still another component is providedbetween the first component and the second component, unless otherwisespecified.

In the specification and the claims, the terms “on”, “above”, “upward”,“below”, “downward” and the like each represent a relative positionalrelationship between the component of interest and another componentwith respect to a surface of a substrate on which an electro-opticalelement is formed (hereinafter, referred to simply as a “surface). Forexample, in this specification, a direction from the surface of thesubstrate toward the electro-optical element is represented by the term“on”, “above” or “upward”, and an opposite direction thereto isrepresented by “below” or “downward.

A “display device” refers to a structural body that displays a video byuse of an electro-optical layer. For example, the “display device” mayrefer to a display cell including an electro-optical layer or may referto a structural body including the display cell and another opticalmember (e.g., polarizing member, backlight unit, touch panel, etc.)attached to the display cell. The “electro-optical layer” may encompassa liquid crystal layer, an electroluminescence (EL) layer, anelectrochromic (EC) layer and an electrophoretic layer, unless anytechnological contradiction occurs. In the following embodiments, anorganic EL display device including an organic EL layer and a liquidcrystal display device including a liquid crystal layer will bedescribed as examples of display device. Nonetheless, the presentinvention is also applicable to any other type of display deviceincluding any electro-optical layer as described above.

Embodiment 1 <Structure of the Display Device>

In this embodiment, an organic EL display device will be described as anexample of display device. The “organic EL display device” is a displaydevice using an organic EL display element as an electro-opticalelement.

FIG. 1 is a plan view showing a structure of an organic EL displaydevice 100 in embodiment 1. Referring to FIG. 1, an array substrate 101includes a plurality of pixels 20 a each including an organic EL element60 (see FIG. 4) formed on a surface of a support substrate (not shown).The array substrate 101 may be referred to also as an “active matrixsubstrate”. In this specification, the array substrate 101 will bedescribed as being separated into three regions, namely, a first region10 a, a second region 10 b and a third substrate 10 c for the sake ofconvenience.

FIG. 1 shows the first region 10 a, the second region 10 b and the thirdregion 10 c as being continuous to each other on one same plane. In theenvironment of actual use, the second region 10 b is curved, so that thefirst region 10 a and the third region 10 c overlap each other as seenin a plan view. FIG. 1 shows a state where the second region 10 b is notcurved for the sake of convenience.

The first region 10 a includes a display region 20 and a peripheralregion 22. In the display region 20, the plurality of pixels 20 a eachincluding an organic EL element 60 are located. In the peripheral region22, circuits (e.g., a shift register circuit and the like) transmittingsignals to the pixels 20 a are located. In this embodiment, there is nospecific limitation on the type of circuits located in the peripheralregion 22.

The second region 10 b includes a curved region along which a terminalregion 24 of the organic EL display device 100 is folded back toward arear surface of the array substrate 101. As described above, in theenvironment of actual use, the second region 10 b is curved, so that thefirst region 10 a and the third region 10 c overlap each other as seenin a plan view.

The third region 10 c includes the terminal region 24. In the terminalregion 24, a plurality of lines 25 are located in a concentrated manner,and the lines 25 are electrically connected with a flexible printedcircuit board 26. A signal (e.g., video signal) transmitted from anexternal device via the flexible printed circuit board 26 is transmittedto the display region 20 via the plurality of lines 25 extending fromthe terminal region 24.

In this embodiment, a driving circuit 28 including an IC chip or thelike is mounted on the flexible printed circuit board 26. The drivingcircuit 28 plays a role of transmitting a control signal such as a startpulse of the like to the shift register circuit or the like located inthe peripheral region 22 or of performing predetermined signalprocessing on the video signal. The driving circuit 28 is notindispensable, and may be omitted. The driving circuit 28 may be locatedin the third region 10 c.

Now, a cross-sectional structure of the organic EL display device 100shown in FIG. 1 taken along one-dot chain line II-II as shown in FIG. 2will be described.

FIG. 2 is a cross-sectional view showing a structure of the organic ELdisplay device 100 in embodiment 1. FIG. 2 specifically shows astructure of the second region 10 b and the vicinity thereof. A firstprotective film 34 is bonded to a surface of the array substrate 101with an adhesive 32 formed of a resin material. In this embodiment, theadhesive 32 is formed of an ultraviolet-curable resin material. It ispreferred that the first protective film 34 is formed of an opticaltransparent film of an organic material such as cycloolefinpolymer(COP), triacetylcellulose (TAC), cycloolefincopolymer (COC) or the like.

On the first protective film 34, a polarizing member 36 is located. Thepolarizing member 36 is bonded to the first protective film 34 with anadhesive (not shown). Below a rear surface of the array substrate 101, asecond protective film 38 is located. The second protective film 38 isbonded to the rear surface of the array substrate 101 with an adhesive,like the first protective film 34, but the adhesive is not shown. It ispreferred that the second protective film 38 is formed of a film of anorganic material such as polyethyleneterephthalate (PET) or the like.

The first protective film 34 may also be referred to as a “laminatefilm”, and has a role of protecting the display region 20. The firstprotective film 34 may be any known protective film.

The polarizing member 36 transmits only light or waves polarized in aspecific direction. Such a polarizing member is usually referred to as a“polarizing plate” or a “polarizing film”. In this embodiment, thepolarizing member 36 is a circularly polarizing film. Use of acircularly polarizing film as the polarizing member 36 decreases thereflectance and suppresses, for example, an image of an observer fromappearing on the display screen.

Like the first protective film 34, the second protective film 38 has arole of protecting the display region 20. Therefore, the secondprotective film 38 is located below the rear surface of the arraysubstrate 101 (surface opposite to the surface on which the adhesive 32is located). The second protective film 38 may be any known protectivefilm.

In this embodiment, the second protective film 38 is not located in thesecond region 10 b. Namely, the second protective film 38 is divided atthe second region 10 b. Such a structure makes it easy to curve thesecond region 10 b.

As shown in FIG. 2, in this embodiment, the adhesive 32 continuouslyextends from the first region 10 a to the third region 10 c. Namely, theadhesive 32 is provided to cover the second region 10 b including thecurved region. Therefore, the adhesive 32 bonding the first protectivefilm 34 to the array substrate 101 also acts as a protective film forthe second region 10 b and the third region 10 c.

Such a structure is realized by applying the adhesive 32 also to thesecond region 10 b and the third region 10 c when the first protectivefilm 34 is bonded to the array substrate 101 with the adhesive 32.

FIG. 3 is a cross-sectional view showing a structure of the organic ELdisplay device 100 in embodiment 1. Specifically, FIG. 3 shows a statewhere the organic EL display device 100 is folded. As shown in FIG. 3,in the environment of actual use of the organic EL display device 100 inthis embodiment, the second region 10 b is curved, and the first region10 a and the third region 10 c overlap each other as seen in a planview. In this embodiment, a spacer 40 is located between the firstregion 10 a and the third region 10 c. A portion of the spacer 40 thatis in contact with the second region 10 b has a curved surface conformedto the shape of the second region 10 b.

In this state, the plurality of lines 25 connecting the display region20 and the terminal region 24 receive a heavy load by the curving of thesecond region 10 b. Conventionally, a protective film is provided on thecurved region to decrease the damage of the lines 25. This requires anextra production step of forming the protective film. The organic ELdisplay device 100 in this embodiment uses the adhesive 32, used to bondthe first protective film 34, also as a protective film for the secondregion 10 b. Thus, the lines 25 in the curved region is protected withno additional production step.

FIG. 2 and FIG. 3 show a structure in which the first protective film 34is bonded to the array substrate 101 and the polarizing member 36 isbonded to the first protective film. The first protective film 34 may beomitted. Namely, the polarizing member 36 may be directly bonded to thearray substrate 101.

<Structure of the Pixel>

Now, a structure of the pixels 20 a of the organic EL display device 100in this embodiment will be described. The pixels 20 a shown in FIG. 1actually each include three sub pixels respectively corresponding to thethree RGB colors. Herein, one sub pixel will be described for the sakeof convenience. In the following, the sub pixel may be referred to asthe “pixel” for the sake of convenience.

FIG. 4 is a cross-sectional view showing a structure of the pixel 20 aof the organic EL display device 100 in embodiment 1. As shown in FIG.4, a thin film transistor 50 is provided on a resin substrate 401 withan underlying film 402 being located between the resin substrate 401 andthe thin film transistor 50. In this embodiment, the resin substrate 401is formed of a resin material such as acrylic resin, polyimide resin orthe like. The underlying film 402 is formed of an inorganic insulatingfilm such as a silicon oxide film or the like. In this embodiment, theresin substrate 401 is used as the support substrate of the arraysubstrate 101. Therefore, the array substrate 101 is flexible. Thus, inthis embodiment, the array substrate 101 may be referred to also as a“flexible substrate”.

The thin film transistor 50 is a so-called top gate-type thin filmtransistor. The thin film transistor 50 is not limited to this, and anytype of thin film transistor is usable instead of the top gate-type thinfilm transistor. The thin film transistor 50 shown in FIG. 4 acts as adriving transistor that supplies an electric current to the organic ELelement 60. In this embodiment, the thin film transistor 50 is anN-channel transistor. The thin film transistor 50 has a known structure,which is not described herein in detail.

The thin film transistor 50 is connected with a storage capacitance 55.The storage capacitance 55 may include any two conductive films amongconductive films included in the thin film transistor 50 and aninsulating film provided between the two conductive films. The storagecapacitance 55 in this embodiment specifically includes a semiconductorlayer forming an active layer of the thin film transistor 50, a gateinsulating film, and a source electrode. The structure of the storagecapacitance 55 is not limited to this.

The thin film transistor 50 is covered with an organic insulating film120. The organic insulating film 120 also acts as a flattening film thatcompensates for roughness caused by the thin film transistor 50 toprovide a flat surface. In this embodiment, the organic insulating film120 is an insulating film containing a resin material such as acrylicresin, polyimide resin or the like.

The organic insulating film 120 has an opening 122 formed therein. Theopening 122 is covered with an organic conductive film 124. In thisembodiment, the organic conductive film 124 is a patterned thin filmformed of a metal oxide material such as ITO (Indium Tin Oxide) or thelike. The organic conductive film 124 is not limited to being formed ofsuch a material, and may be formed of any other oxide conductive film.The organic conductive film 124 is connected with a part of the thinfilm transistor 50 exposed by the opening 122 (the part is,specifically, the source electrode).

On a top surface of the organic insulating film 120, a lower electrode126, of a storage capacitance 57, formed of an oxide conductive film isprovided. The lower electrode 126 is formed in the same step as that ofthe organic conductive film 124. The lower electrode 126 is providedbelow the organic EL element 60. As described below, the organic ELelement 60 in this embodiment is configured to output light upward.Therefore, a space below the organic EL element 60 is usable to form thestorage capacitance 57.

Although not shown in FIG. 4, the oxide conductive film used to form theoxide conductive film 124 and the lower electrode 126 of the storagecapacitance 57 may also be used for another use (e.g., to form a line).In such a case, a metal film may be provided on the oxide conductivefilm used to form the line, so that the line resistance may bedecreased. An oxide conductive film formed of a metal oxide has a higherresistance than that of a metal film. Therefore, in the case where suchan oxide conductive film is used to form a line, it is preferred that ametal film is provided thereon to decrease the resistance of theassembly of the oxide conductive film and the metal film. In this case,the oxide conductive film 124 also acts as a protective film thatprotects the source electrode of the thin film transistor 50 againstetching gas used to form the metal film.

On the oxide conductive film 124 and the lower electrode 126, aninorganic insulating film 128 is provided. In this embodiment, theinorganic insulating film 128 is formed of a silicon nitride film. Theinorganic insulating film 128 is not limited to this, and may be formedof any other inorganic insulating film such as a silicon oxide film orthe like. The inorganic insulating film 128 has an opening 130 a formedtherein, which exposes the organic insulating film 120. The opening 130a acts as a water releasing region 65. The water releasing region 65plays a role of releasing moisture or the like generated from theorganic insulating film 120 in a heating step performed after theorganic insulating film 120 is formed.

On the inorganic insulating film 128, a pixel electrode 132 is provided.The pixel electrode 132 is connected with the oxide conductive film 124via an opening 130 b provided in the inorganic insulating film 128.Namely, the pixel electrode 132 is connected with the thin filmtransistor 50 via the oxide conductive film 124. The pixel electrode 132acts as an upper electrode of the storage capacitance 57 and also actsas an anode electrode of the organic EL element 60.

In this embodiment, the pixel electrode 132 is formed of a conductivefilm having a stack structure including oxide conductive films of ITO orthe like and a thin film containing silver held between the oxideconductive films. The pixel electrode 132 is not limited to having sucha structure. In order to allow light emitted from the organic EL element60 to be output upward, it is preferred that the pixel electrode 132includes a reflective conductive film.

In this embodiment, the dielectric material of the storage capacitance57 is the silicon nitride film having a higher dielectric constant thanthat of the other insulating films. This provides an advantage that thestorage capacitance 57 has an advantage of having a large capacitanceeasily. In addition, the space below the organic EL element 60 iseffectively used to locate the storage capacitance 57, which provides anadvantage that the area size of the storage capacitance 57 is made largeeasily.

The pixel electrode 132 is partially covered with a bank 134 formed ofan organic material. Specifically, the bank 134 covers an end portion ofthe pixel electrode 132, and has an opening 136 exposing a part of a topsurface of the pixel electrode 132. The part of the top surface of thepixel electrode 132 thus exposed is substantially a light emittingregion of the pixel 20 a. Namely, the bank 134 plays a role of definingthe light emitting region of the pixel 20 a. The organic material usedto form the bank 134 may be a resin material such as an acrylic resin, apolyimide resin or the like, but is not limited to any of these.

On a region of the top surface of the pixel electrode 132 that does notoverlap the bank (namely, a region in the opening 136), an organic ELlayer 138 is provided. In this embodiment, the organic EL layer 138 isformed by vapor deposition of an organic EL material. The organic ELlayer 138 includes at least a light emitting layer (not shown), and mayalso include an electron injection layer, an electron transfer layer, anelectron blocking layer, a hole injection layer, a hole transfer layerand/or a hole blocking layer. The organic EL layer 138 may be formed ofan organic EL material that emits light of at least, for example, red,blue or green.

In this embodiment, the light emitting layer emits light of a differentcolor on a pixel-by-pixel basis, for example. The light emitting layeris not limited to this. For example, an organic EL layer emitting whitelight may be provided in each of a plurality of pixels, although such astructure is not shown. In this case, the white light is provided withany color of the RGB colors by a color filter provided in each pixel.The functional layer(s) such as the electron injection layer, theelectron transfer layer, the electron blocking layer, the hole injectionlayer, the hole transfer layer and/or the hole blocking layer may beprovided across a plurality of pixels.

On the organic EL layer 138, a common electrode 140 formed of aconductive film containing an alkaline metal material is provided. Thealkaline metal material may be, for example, magnesium (Mg), lithium(Li) or the like. In this embodiment, a film of MgAg, which is an alloyof magnesium and silver, is used as the conductive film containing analkaline metal material. The common electrode 140 acts as a cathodeelectrode of the organic EL element 60. The common electrode 140 isprovided across a plurality of pixels.

In the case where the organic EL display device 100 is of a top emissiontype, in which the light from the organic EL element 60 is outputupward, namely, output through the common electrode 140, the commonelectrode 140 needs to be light-transmissive. In the case where thecommon electrode 140 is formed of a conductive film containing analkaline metal material as described above, the common electrode 140 ismade light-transmissive by being thinned sufficiently to transmit thelight. Specifically, the thickness of the common electrode 140 may be 10nm or greater and 30 nm or less to be light-transmissive.

On the common electrode 140, a sealing film 142 is provided. The sealingfilm 142 in this embodiment includes three layers, specifically, a firstsealing film 142 a formed of an inorganic material, a second sealingfilm 142 b formed of an organic material, and a third sealing film 142 cformed of an inorganic material sequentially from the lowest layer.These sealing films play a role of preventing entrance of moisture orthe like from outside to prevent deterioration of the organic EL layer138 and the common electrode 140.

In this embodiment, the first sealing film 142 a and the third sealingfilm 142 c are each formed of a silicon nitride film. The first sealingfilm 142 a and the third sealing film 142 c are not limited to this, andmay be formed of a silicon oxide film instead. Namely, the first sealingfilm 142 a and the third sealing film 142 c may be each formed of anorganic insulating film. It is especially preferred that the organicinsulating film contains a silicon nitride.

The second sealing film 142 b is an organic insulating film formed of aresin material. In this embodiment, an organic insulating film formed ofa resin material is used as the second sealing film 142 b, so thatroughness caused by the bank 134 is compensated for and a flat surfaceis provided. The first sealing film 142 a, which has a thickness ofabout 1 μm, is formed along an inclining surface of the bank 134. Bycontrast, the second sealing film 142 b, which has a thickness of about10 μm, is sufficient to fill the opening 136 provided in the bank 134.Therefore, use of an organic insulating film as the second sealing film142 b allows roughness at a top surface of the second sealing film 142 bto be smaller than roughness at a top surface of the first sealing film142 a.

<Structure of the End Portion and the Vicinity of the Display Region>

Now, a specific structure of an end portion and the vicinity of thedisplay region 20 will be described. More specifically, a structure ofthe adhesive 32 in the region bridging the first region 10 a and thesecond region 10 b shown in FIG. 1 will be described.

FIG. 5 is a cross-sectional view showing a structure of the end portionand the vicinity thereof of the display region 20 of the organic ELdisplay device 100 in embodiment 1. As described above, the pixel 20 aincludes the thin film transistor 50 and the organic EL element 60. Thedetailed structure of the pixel 20 a are as described above withreference to FIG. 4. The common electrode 140 acting as the cathodeelectrode of the organic EL element 60 is electrically connected withthe lines 25 in the vicinity of the display region 20. Although notshown in FIG. 5, the plurality of lines 25 are arrayed side by side in adepth direction of the sheet of FIG. 5 as can be understood from FIG. 1.

In this embodiment, the common electrode 140 is electrically connectedwith the lines 25 via a connection electrode 148. The connectionelectrode 148 may be formed of an oxide conductive film, like the pixelelectrode 132. Specifically, the connection electrode 148 may be formedin the same step as that of the pixel electrode 132.

As shown in FIG. 5, neither the organic insulating film 120 nor thesecond sealing film 142 b is provided in a region 150 outer to theconnection electrode 148 (outside on the side where the second region120 b is located). Therefore, in the region 150, a stack structure ofthe inorganic insulating film 128, the first sealing film 142 a and thethird sealing film 142 c is provided. Thus, entrance of the moisture orthe like from outside via the organic material is suppressed.

Outer to the region 150, a protruding portion 152 formed in the samestep as that of the organic insulating film 120 is located. In a step offorming a mask insulating film 154, the protruding portion 152 acts as abank that stops expansion of a resin material. The mask insulating film154 is formed by the resin material dripped to the center or thevicinity thereof of the display region 20 being expanded externally andthen cured. At this point, the protruding portion 152 plays a role ofstopping the expansion of the resin material.

The first sealing film 142 a and the second sealing film 142 b areremoved from the second region 10 b and the third region 10 c by etchingin order to expose the lines 25 in the terminal region 24. In the stepof etching performed to remove the first sealing film 142 a and thesecond sealing film 142 b, the mask insulating film 154 acts as a mask.In this embodiment, the mask insulating film 154 extends to a positionabove the protruding portion 152. Therefore, ends of the first sealingfilm 142 a and the second sealing film 142 b are also located above theprotruding portion 152. The time duration of the etching may becontrolled such that the inorganic insulating film 128 is left as inthis embodiment.

The adhesive 32 is provided on the mask insulating film 154. In thisembodiment, the polarizing member 36 is bonded to the mask informationfilm 154 with the adhesive 32. As described above, the adhesive 32extends continuously from the first region 10 a to the third region 10c. As shown in FIG. 5, the adhesive 32 is provided continuously from thefirst region 10 a to the third region 10 c while covering the endportion and the vicinity of the display region 20. The adhesive 32 mayhave a thickness greater than that of a resin substrate 401. Thethickness of the adhesive 32 may be set to any value. Basically, theadhesive 32 is less hard, less rigid and less elastic than the resinsubstrate 401. In order to allow a neutral surface to be located in, orin the vicinity of, the lines, the inorganic insulating film or the likelocated in the second region 10 b when the second region 10 b is folded,it is preferred that the adhesive 32 is thicker than the resin substrate401 in consideration of the above-described elasticity or the like.Therefore, in this embodiment, the adhesive 32 is thicker than the resinsubstrate 401.

As described above, in the organic EL display device 100 in thisembodiment, the adhesive 32 used to bond the first protective film 34 orthe polarizing member 36 located on the display region 20 is provided inthe first region 10 a and extends to the third region 10 c from thefirst region 10 a. With such a structure, the curved region included inthe second region 10 b is covered with the adhesive 32 formed of a resinmaterial with no additional production step. Thus, the lines 25 areprotected in the curved region by such a simple method.

In this embodiment, an ultraviolet-curable resin material is used as theadhesive 32. Namely, the ultraviolet rays may be directed to polymerizeand thus cure a monomer in the resin material. For example, the adhesive32 may be irradiated with ultraviolet rays in the state where the secondregion 10 b is curved as shown in FIG. 3, so that the adhesive 32 iscured while the second region 10 b is kept curved. This is merely anexample, and does not eliminate use of a thermosetting resin material asthe adhesive 32.

In the case where an ultraviolet-curable resin material is used as theadhesive 32, it is preferred that the ultraviolet-curable resin materialis curable by ultraviolet rays in a wavelength range that does notdamage the organic EL layer 138. In the case where such anultraviolet-curable resin material is not used, it is preferred that thedisplay region 20 is not irradiated with ultraviolet rays inconsideration of the damage to the organic EL layer 138. Namely, it ispreferred that the ultraviolet rays are locally directed to the secondregion 10 b to selectively cure the adhesive 32. In this case, theportion of the adhesive 32 irradiated with the ultraviolet rays ispolymerized, and therefore, the degree of polymerization of the resinmaterial in this region is increased. Namely, in the case where theadhesive 32 is selectively cured, a portion of the adhesive 32 in thecurved region (in the second region 10 b) has a higher degree ofpolymerization than that of a portion of the adhesive 32 in the displayregion 20.

It is preferred that a region outer to the display region 20 (namely, apart of the first region 10 a, the entirety of the second region 10 band the entirety of the third region 10 c) is cured by ultraviolet rays,for the following reason. In the case where a border between theabove-described region having a high degree of polymerization and aregion having a low degree of polymerization is outer to the end of thefirst protective film 34, the adhesive 32 may possibly be broken fromthe border.

In this embodiment, the adhesive 32 is continuously formed across theend of the first protective film 34, without being changed in thematerial or state. Therefore, in the case where the adhesive 32 and anorganic film that maintains the neutral surface are formed separately, aproblem that the organic film is delaminated at the border of theadhesive 32 and the organic film is avoided.

Embodiment 2

In this embodiment, a liquid crystal display device will be described asan example of display device. The liquid crystal display device uses aliquid crystal element as the electro-optical element. In thisembodiment, components same as those in the organic EL display device100 in embodiment 1 will bear the same reference numerals therewith anddescriptions thereof may be omitted.

FIG. 6 is a cross-sectional view showing a structure of a liquid crystaldisplay device 200 in embodiment 2. On the surface of an array substrate201, a counter substrate 202 is provided with a liquid crystal layer 42being located between the array substrate 201 and the counter substrate202. The liquid crystal layer 42 is enclosed by a sealing member 44 andsealed between the array substrate 201 and the counter substrate 202. Inthis embodiment, the sealing member 44 is provided to enclose thedisplay region 20 and also the second region 10 b. Namely, the sealingmember 44 continuously extends from the first region 10 a to the thirdregion 10 c. Therefore, the sealing member 44 formed of a resin materialacts as a resin layer protecting the second region 10 b and also is incontact with the liquid crystal layer 42 included in the liquid crystalelement.

The structure shown in FIG. 6 is realized as follows. In the step offorming the sealing 44 by use of a dispenser or the like, a resinmaterial forming the sealing member 44 is also applied to the secondregion 10 b and the third region 10 c. Specifically, first, thedispenser is moved to enclose the display region 20 to form a memberthat seals the liquid crystal layer 42. Then, the dispenser is scannedfrom the display region 20 to the third region 10 b to form a thin filmformed of a resin material.

The sealing member 44 may be formed of an ultraviolet-curable resinmaterial or a thermosetting resin material. Alternatively, a resinmaterial curable by both of ultraviolet rays and heat may be used. Ineither case, in this embodiment, the sealing member 44 acts as a memberthat seals the liquid crystal layer 42 and also as a protective memberfor the curved region. Therefore, the second region 10 b including thecurved region is protected by the resin layer approximately as thick asthe liquid crystal layer 42.

The first protective film 34 is bonded to the counter substrate 202 withan adhesive (not shown). A first polarizing member 36 a is bonded to thefirst protective film 34 with an adhesive (not shown). Below the rearsurface of the array substrate 201, the second protective film 38 islocated. The second protective film 38 is bonded to the rear surface ofthe array substrate 201 with the adhesive, like the first protectivefilm 34. A second polarizing member 36 b is bonded to the secondprotective film 38 with an adhesive (not shown). The first polarizingmember 36 a and the second polarizing member 36 b are located in acrossed Nichols state.

FIG. 7 is a cross-sectional view showing a structure of the liquidcrystal display device 200 in embodiment 2. Specifically, FIG. 7 shows astate where the liquid crystal display device 200 is curved. As shown inFIG. 7, in the environment of use of the liquid crystal display device200 in this embodiment, the second region 10 b is curved, and the firstregion 10 b and the third region 10 c overlap each other as seen in aplan view.

As shown in FIG. 7, the liquid crystal display device 200 in thisembodiment includes a light guide plate 46 located adjacent to thesecond polarizing member 36 b. A light source 48 formed of an LED lampor the like is located at a side surface of the light guide plate 46. Anoptical component including the light guide plate 46 and the lightsource 48 may be referred to as a “backlight unit”.

In this embodiment, in the state where the second region 10 b is curved,the third region 10 c and the light guide plate 46 overlap each other asseen in a plan view. Namely, in the liquid crystal display device 200 inthis embodiment, the second polarizing member 36 b and the light guideplate 46 are located between the first region 10 a and the third region10 c. Such a structure allows the liquid crystal display device 200 tobe compact.

In this embodiment, a spacer 52 is located at a position correspondingto the second region 10 b (i.e., at the curved portion). A portion ofthe spacer 52 that is in contact with the second region 10 b is curvedso as to be conformed to the shape of the second region 10 b. A part ofthe spacer 52 is located between the first region 10 a and the thirdregion 10 c.

In the liquid crystal display device 200 in this embodiment, the sealingmember 44 used to seal the liquid crystal layer 42 is also used as aprotective film for the second region 10 b. Therefore, the lines in thecurved region are protected with no additional production step.

FIG. 6 and FIG. 7 show a structure in which the first protective film 34is bonded to the counter substrate 202 and the first polarizing member36 a is bonded to the first protective film 34. The first protectivefilm 34 may be omitted. Namely, the first polarizing member 36 a may bedirectly bonded to the counter substrate 202. Similarly, the secondprotective film 38 may be omitted, and the second polarizing member 36 bmay be directly bonded to the array substrate 201.

Embodiment 3

In each of the above-described embodiments, the array substrate 101 (orthe array substrate 201) is curved along a region between the displayregion 20 and the terminal region 24. The present invention is notlimited to this. For example, in the case where, as shown in FIG. 1, theterminal region 24 is located below the display region 20, the arraysubstrate 101 (or the array substrate 201) may be curved along a portionparallel to a left side, a right side or a top side thereof according tothe present invention.

The present invention is applicable to a display device that may befolded along a portion in the display screen, like a foldable displaydevice. For example, two or four display regions each enclosed by asealing member may be formed on a resin substrate, and one displayscreen may be formed of such a plurality of display regions. In thiscase, the array substrate may be curved along the portion between theplurality of display regions. The sealing member may extend on thecurved region to act as a protective film.

The above-described embodiments according to the present invention maybe optionally combined as long as no contradiction occurs. The displaydevices described above in embodiments according to the presentinvention may have an element added thereto, or deleted therefrom, ormay be changed in design optionally by a person of ordinary skill in theart. The methods described above in embodiments according to the presentinvention may have a step added thereto, or deleted therefrom, or may bechanged in the condition optionally by a person of ordinary skill in theart. Such devices and methods are encompassed in the scope of thepresent invention as long as including the gist of the presentinvention.

Even functions and effects that are different from those provided by theabove-described embodiments but are obvious from the description of thisspecification or are easily expectable by a person of ordinary skill inthe art are naturally construed as being located by the presentinvention.

What is claimed is:
 1. A display device, comprising: a flexiblesubstrate including a first region including a display region, a secondregion including a curved region, and a third region including aterminal region; an electro-optical element located in the displayregion; and a resin layer continuously extending from the first regionto the third region.
 2. The display device according to claim 1, whereinthe electro-optical element is an organic EL element, and in the displayregion, the resin layer is located on the organic EL element.
 3. Thedisplay device according to claim 2, wherein the resin layer is anadhesive bonding a protective film or a polarizing member to the organicEL layer.
 4. The display device according to claim 3, wherein the resinlayer has a higher degree of polymerization in the curved region than inthe display region.
 5. The display device according to claim 2, whereinin the first region, the resin layer is provided on another resin layerprovided on the organic EL layer.
 6. The display device according toclaim 1, wherein the resin layer is thicker than the flexible substrate.7. The display device according to claim 1, wherein the electro-opticalelement is a liquid crystal element, and a side surface of the resinlayer is in contact with a liquid crystal layer included in the liquidcrystal element.
 8. The display device according to claim 7, wherein theresin layer is a sealing member enclosing the liquid crystal layer. 9.The display device according to claim 7, wherein the resin layer isapproximately as thick as the liquid crystal layer.
 10. The displaydevice according to claim 7, further comprising a protective film or apolarizing member on the liquid crystal layer, wherein a part of theresin layer overlaps the protective film or the polarizing member asseen in a plan view.
 11. The display device according to claim 1,wherein the resin layer covers the curved region.
 12. The display deviceaccording to claim 1, further comprising a protective film divided atthe curved region, the protective film being provided below a surface ofthe flexible substrate opposite to a surface on which the resin layer islocated.